I know what you mean about being mistaken for younger. I'm also 24 and I don't even wait to be carded anymore. I have my I.D. out and ready
Two years when I was 22 I went to a movie and before going into the theatre, an usher said "you have to be 17 to see this movie." This was after I had already shown I.D. at the ticket window. I'm also only 5'0 tall and I find that the combination of looking young anyway plus being short sometimes makes people talk to me as if I'm a child. I have a salon appointment for tomorrow, but don't know if I want to go too much shorter. My hair needs some length and weight for control. Maybe a different more "adult" style is what I need. I'm not complaining too much I'll be glad for this when I'm older. Maybe I should have a more sophisticated cut now and then when I get older let it grow out more.